Air suspensions are often utilized in off-road vehicles; however, operational performance of these off-road vehicles can be limited by roll stiffness of the suspension. Roll stiffness limits an articulation angle of the suspension and keeps some vehicle tires from contacting the ground under certain off-road conditions. For example, uneven ground can cause one wheel to have ground contact while a laterally opposite wheel remains out of contact with the ground due to the limited articulation of the suspension.
One solution has been to use a crossover valve in an axle to vary stiffness as needed between laterally opposed springs in an attempt to maintain four wheel contact with the ground. The crossover valve attenuates stiffness by allowing air from one spring on one side of the vehicle to be communicated to a laterally opposite spring on the other side of the vehicle. For a typical four-wheel drive vehicle, one crossover valve is used on a front axle to allow air communication between front right and front left springs, and another crossover valve is used on a rear axle to allow air communication between rear right and rear left springs.
The inclusion of the two crossover valves is disadvantageous from a cost and material perspective. Further, due to limited packaging space, it is a challenge to route and plumb the crossover valves into the suspension.
Thus, there is a need for a more cost effective suspension control that provides desired stiffness attenuation in addition to overcoming other deficiencies in the prior art as outlined above.